Merge branch '2.8' into 3.1

* 2.8:
  Fix deprecated swiftmailer parameter

Author: fabpot

app/config/config_dev.yml

@@ -31,4 +31,4 @@ monolog:
         #    level:  info
 
 #swiftmailer:
-#    delivery_address: me@example.com
+#    delivery_addresses: ['me@example.com']

composer.json

@@ -16,7 +16,7 @@
         "doctrine/orm": "^2.5",
         "doctrine/doctrine-bundle": "^1.6",
         "doctrine/doctrine-cache-bundle": "^1.2",
-        "symfony/swiftmailer-bundle": "^2.3",
+        "symfony/swiftmailer-bundle": "^2.3.10",
         "symfony/monolog-bundle": "~2.11.3",
         "symfony/polyfill-apcu": "^1.0",
         "sensio/distribution-bundle": "^5.0",